SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '357a235e425ca3f6167854f9bbe31de625fbe1902658458b6c3b814a59bb8b3f' 
  AND token = 'eQf//6WYgk0iYbwZwjuQNKvjyBawvjLfpYElP3su7M4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}